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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 19:46:40 +07:00
9e3a4afd5a
When fixing up invalid years rtc_read_alarm() was calling rtc_valid_tm() as a boolean but rtc_valid_tm() returns zero on success or a negative number if the time is not valid so the test was inverted. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
471 lines
12 KiB
C
471 lines
12 KiB
C
/*
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* RTC subsystem, interface functions
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*
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* Copyright (C) 2005 Tower Technologies
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* based on arch/arm/common/rtctime.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/rtc.h>
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#include <linux/log2.h>
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int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
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{
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int err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->read_time)
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err = -EINVAL;
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else {
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memset(tm, 0, sizeof(struct rtc_time));
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err = rtc->ops->read_time(rtc->dev.parent, tm);
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}
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_read_time);
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int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
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{
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int err;
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err = rtc_valid_tm(tm);
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if (err != 0)
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return err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->set_time)
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err = -EINVAL;
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else
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err = rtc->ops->set_time(rtc->dev.parent, tm);
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_time);
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int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
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{
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int err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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if (!rtc->ops)
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err = -ENODEV;
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else if (rtc->ops->set_mmss)
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err = rtc->ops->set_mmss(rtc->dev.parent, secs);
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else if (rtc->ops->read_time && rtc->ops->set_time) {
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struct rtc_time new, old;
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err = rtc->ops->read_time(rtc->dev.parent, &old);
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if (err == 0) {
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rtc_time_to_tm(secs, &new);
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/*
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* avoid writing when we're going to change the day of
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* the month. We will retry in the next minute. This
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* basically means that if the RTC must not drift
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* by more than 1 minute in 11 minutes.
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*/
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if (!((old.tm_hour == 23 && old.tm_min == 59) ||
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(new.tm_hour == 23 && new.tm_min == 59)))
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err = rtc->ops->set_time(rtc->dev.parent,
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&new);
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}
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}
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else
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err = -EINVAL;
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_mmss);
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static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
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{
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int err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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if (rtc->ops == NULL)
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err = -ENODEV;
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else if (!rtc->ops->read_alarm)
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err = -EINVAL;
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else {
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memset(alarm, 0, sizeof(struct rtc_wkalrm));
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err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
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}
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
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{
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int err;
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struct rtc_time before, now;
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int first_time = 1;
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unsigned long t_now, t_alm;
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enum { none, day, month, year } missing = none;
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unsigned days;
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/* The lower level RTC driver may return -1 in some fields,
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* creating invalid alarm->time values, for reasons like:
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*
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* - The hardware may not be capable of filling them in;
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* many alarms match only on time-of-day fields, not
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* day/month/year calendar data.
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*
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* - Some hardware uses illegal values as "wildcard" match
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* values, which non-Linux firmware (like a BIOS) may try
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* to set up as e.g. "alarm 15 minutes after each hour".
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* Linux uses only oneshot alarms.
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*
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* When we see that here, we deal with it by using values from
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* a current RTC timestamp for any missing (-1) values. The
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* RTC driver prevents "periodic alarm" modes.
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*
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* But this can be racey, because some fields of the RTC timestamp
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* may have wrapped in the interval since we read the RTC alarm,
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* which would lead to us inserting inconsistent values in place
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* of the -1 fields.
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*
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* Reading the alarm and timestamp in the reverse sequence
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* would have the same race condition, and not solve the issue.
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*
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* So, we must first read the RTC timestamp,
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* then read the RTC alarm value,
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* and then read a second RTC timestamp.
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*
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* If any fields of the second timestamp have changed
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* when compared with the first timestamp, then we know
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* our timestamp may be inconsistent with that used by
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* the low-level rtc_read_alarm_internal() function.
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*
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* So, when the two timestamps disagree, we just loop and do
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* the process again to get a fully consistent set of values.
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*
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* This could all instead be done in the lower level driver,
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* but since more than one lower level RTC implementation needs it,
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* then it's probably best best to do it here instead of there..
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*/
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/* Get the "before" timestamp */
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err = rtc_read_time(rtc, &before);
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if (err < 0)
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return err;
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do {
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if (!first_time)
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memcpy(&before, &now, sizeof(struct rtc_time));
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first_time = 0;
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/* get the RTC alarm values, which may be incomplete */
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err = rtc_read_alarm_internal(rtc, alarm);
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if (err)
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return err;
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if (!alarm->enabled)
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return 0;
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/* full-function RTCs won't have such missing fields */
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if (rtc_valid_tm(&alarm->time) == 0)
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return 0;
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/* get the "after" timestamp, to detect wrapped fields */
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err = rtc_read_time(rtc, &now);
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if (err < 0)
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return err;
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/* note that tm_sec is a "don't care" value here: */
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} while ( before.tm_min != now.tm_min
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|| before.tm_hour != now.tm_hour
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|| before.tm_mon != now.tm_mon
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|| before.tm_year != now.tm_year);
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/* Fill in the missing alarm fields using the timestamp; we
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* know there's at least one since alarm->time is invalid.
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*/
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if (alarm->time.tm_sec == -1)
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alarm->time.tm_sec = now.tm_sec;
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if (alarm->time.tm_min == -1)
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alarm->time.tm_min = now.tm_min;
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if (alarm->time.tm_hour == -1)
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alarm->time.tm_hour = now.tm_hour;
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/* For simplicity, only support date rollover for now */
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if (alarm->time.tm_mday == -1) {
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alarm->time.tm_mday = now.tm_mday;
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missing = day;
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}
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if (alarm->time.tm_mon == -1) {
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alarm->time.tm_mon = now.tm_mon;
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if (missing == none)
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missing = month;
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}
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if (alarm->time.tm_year == -1) {
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alarm->time.tm_year = now.tm_year;
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if (missing == none)
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missing = year;
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}
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/* with luck, no rollover is needed */
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rtc_tm_to_time(&now, &t_now);
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rtc_tm_to_time(&alarm->time, &t_alm);
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if (t_now < t_alm)
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goto done;
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switch (missing) {
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/* 24 hour rollover ... if it's now 10am Monday, an alarm that
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* that will trigger at 5am will do so at 5am Tuesday, which
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* could also be in the next month or year. This is a common
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* case, especially for PCs.
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*/
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case day:
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dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
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t_alm += 24 * 60 * 60;
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rtc_time_to_tm(t_alm, &alarm->time);
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break;
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/* Month rollover ... if it's the 31th, an alarm on the 3rd will
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* be next month. An alarm matching on the 30th, 29th, or 28th
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* may end up in the month after that! Many newer PCs support
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* this type of alarm.
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*/
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case month:
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dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
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do {
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if (alarm->time.tm_mon < 11)
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alarm->time.tm_mon++;
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else {
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alarm->time.tm_mon = 0;
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alarm->time.tm_year++;
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}
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days = rtc_month_days(alarm->time.tm_mon,
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alarm->time.tm_year);
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} while (days < alarm->time.tm_mday);
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break;
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/* Year rollover ... easy except for leap years! */
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case year:
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dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
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do {
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alarm->time.tm_year++;
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} while (rtc_valid_tm(&alarm->time) != 0);
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break;
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default:
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dev_warn(&rtc->dev, "alarm rollover not handled\n");
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}
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done:
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return 0;
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}
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EXPORT_SYMBOL_GPL(rtc_read_alarm);
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int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
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{
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int err;
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err = rtc_valid_tm(&alarm->time);
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if (err != 0)
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return err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->set_alarm)
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err = -EINVAL;
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else
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err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_alarm);
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/**
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* rtc_update_irq - report RTC periodic, alarm, and/or update irqs
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* @rtc: the rtc device
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* @num: how many irqs are being reported (usually one)
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* @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
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* Context: in_interrupt(), irqs blocked
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*/
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void rtc_update_irq(struct rtc_device *rtc,
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unsigned long num, unsigned long events)
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{
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spin_lock(&rtc->irq_lock);
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rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
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spin_unlock(&rtc->irq_lock);
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spin_lock(&rtc->irq_task_lock);
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if (rtc->irq_task)
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rtc->irq_task->func(rtc->irq_task->private_data);
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spin_unlock(&rtc->irq_task_lock);
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wake_up_interruptible(&rtc->irq_queue);
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kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
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}
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EXPORT_SYMBOL_GPL(rtc_update_irq);
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static int __rtc_match(struct device *dev, void *data)
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{
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char *name = (char *)data;
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if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0)
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return 1;
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return 0;
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}
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struct rtc_device *rtc_class_open(char *name)
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{
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struct device *dev;
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struct rtc_device *rtc = NULL;
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dev = class_find_device(rtc_class, NULL, name, __rtc_match);
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if (dev)
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rtc = to_rtc_device(dev);
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if (rtc) {
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if (!try_module_get(rtc->owner)) {
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put_device(dev);
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rtc = NULL;
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}
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}
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return rtc;
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}
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EXPORT_SYMBOL_GPL(rtc_class_open);
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void rtc_class_close(struct rtc_device *rtc)
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{
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module_put(rtc->owner);
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put_device(&rtc->dev);
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}
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EXPORT_SYMBOL_GPL(rtc_class_close);
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int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
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{
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int retval = -EBUSY;
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if (task == NULL || task->func == NULL)
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return -EINVAL;
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/* Cannot register while the char dev is in use */
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if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
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return -EBUSY;
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spin_lock_irq(&rtc->irq_task_lock);
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if (rtc->irq_task == NULL) {
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rtc->irq_task = task;
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retval = 0;
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}
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spin_unlock_irq(&rtc->irq_task_lock);
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clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
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return retval;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_register);
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void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
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{
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spin_lock_irq(&rtc->irq_task_lock);
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if (rtc->irq_task == task)
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rtc->irq_task = NULL;
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spin_unlock_irq(&rtc->irq_task_lock);
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}
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EXPORT_SYMBOL_GPL(rtc_irq_unregister);
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/**
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* rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
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* @rtc: the rtc device
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* @task: currently registered with rtc_irq_register()
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* @enabled: true to enable periodic IRQs
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* Context: any
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*
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* Note that rtc_irq_set_freq() should previously have been used to
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* specify the desired frequency of periodic IRQ task->func() callbacks.
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*/
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int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
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{
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int err = 0;
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unsigned long flags;
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if (rtc->ops->irq_set_state == NULL)
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return -ENXIO;
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spin_lock_irqsave(&rtc->irq_task_lock, flags);
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if (rtc->irq_task != NULL && task == NULL)
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err = -EBUSY;
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if (rtc->irq_task != task)
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err = -EACCES;
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spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
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if (err == 0)
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err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_set_state);
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/**
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* rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
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* @rtc: the rtc device
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* @task: currently registered with rtc_irq_register()
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* @freq: positive frequency with which task->func() will be called
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* Context: any
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*
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* Note that rtc_irq_set_state() is used to enable or disable the
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* periodic IRQs.
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*/
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int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
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{
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int err = 0;
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unsigned long flags;
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if (rtc->ops->irq_set_freq == NULL)
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return -ENXIO;
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if (!is_power_of_2(freq))
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return -EINVAL;
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spin_lock_irqsave(&rtc->irq_task_lock, flags);
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if (rtc->irq_task != NULL && task == NULL)
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err = -EBUSY;
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if (rtc->irq_task != task)
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err = -EACCES;
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spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
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if (err == 0) {
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err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);
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if (err == 0)
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rtc->irq_freq = freq;
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
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